1. Field of the Invention
The present invention relates to a film magazine which contains photographic film wound around a spool in the form of a roll and a camera to which the film magazine is attached. More particularly, this invention is concerned with a film magazine having a function which indicates the film use status distinguishing whether the film is unused, used partially and extracted in the middle, or used up fully (exposed), and a camera to which the film magazine is attached.
2. Related Background Art
In general, photographic film is handled in a state in which the film is contained in a magazine or a simple container having a shading function, and well-protected from being exposed when it is attached to or extracted from a camera, kept in storage, or carried here and there.
For the film magazine, it must be identified whether film contained in the magazine is unused or used up (exposed). For a typical 35-mm film magazine, by checking whether the film end comes out of a slot of the magazine, it is determined whether film contained inside is unused or exposed. That is to say, when film is rewound at completion of exposure, the film and the film end inclusive are usually wound up into the magazine. By checking whether the film end is wound up or not, it can be distinguished whether the film is unused or exposed.
However, when a film use status is distinguished by checking whether the film end comes out of the magazine as mentioned above, if the film is rewound at completion of photography, the film end must be wound up inside the magazine without fail. This operation, however, lacks for certainty. Therefore, this method cannot be said to be reliable. In particular, assuming that the film end comes out of a magazine for some reason, if the film is extracted from a camera and stored temporarily, the film may be recognized as an unused film mistakenly. If such a magazine is attached to the camera, since photography can be done, a problem of a double exposure occurs.
Some photographers do not expose film attached to a camera up to the last frame, but rewind it in the middle Of feeding and extract it from the camera. Then, the film is re-attached to the camera and the remaining portion of the film is exposed. During the rewinding, a special precaution is needed so as not to wind the film end into the magazine. In this case, the film is always stored with its end out of the magazine. The magazine cannot be differentiated from a new one.
Therefore, some photographers write the use status of film in a magazine down on the outer surface of the magazine or a housing case. This is a nuisance. Some measure must be taken to solve these problems.
A magazine for containing film is proposed, for example, in the specification of the U.S. Pat. Nos. 4,832,275 or 4,482,232, wherein the film end is always drawn into the magazine when the magazine is unattached. In such a magazine, a distinguishing method using the film end cannot be adopted for the foregoing 35-mm film magazine. Even if exposed film is attached to a camera, photography can be performed. This is accompanied with the aforesaid problem of a double exposure. In this type of a magazine, some measure must be taken to allow a photographer to check whether film is unused, extracted in the middle, or used lap fully (exposed).